JP7029136B2 - Construction method of filler in the underground pipe structure and underground pipe structure - Google Patents

Description

The present invention relates to a method of constructing a filler in an underground pipe structure.

A plurality of pipelines (communication pipelines) through which cables such as optical fiber cables pass are laid in the ground. In places where roads and railroads pass, Hume pipes are installed for the purpose of protecting this pipe from the load on the ground, and a double pipe structure with multiple pipes as inner pipes and Hume pipes as outer pipes is used. Nothing. The end of the Hume pipe is closed with bricks, etc., and there is a hollow space between the inner pipe and the outer pipe. In such a double pipe structure, earth and sand flow into the outer pipe due to deterioration of the pipe end blockage and the outer pipe joint, creating a gap in the soil on the pipe and sinking the above-ground structure such as a road. There is a risk of rushing.
As a countermeasure against this, a method has been devised in which a filler containing cement is filled between the inner pipe and the outer pipe to prevent the inflow of earth and sand into the pipe and prevent the depression (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2009-1446

However, the filler using cement has a drawback that it generates heat when mixed with water for hardening. In particular, when a cable such as an optical fiber exists in the inner pipe, when the filler is filled between the inner pipe and the outer pipe, the communication in the inner pipe is performed for the reasons shown in (A) and (B) below. There is a risk of causing damage to the cable and deterioration of performance, and there is a risk that the filling material is not sufficiently filled in the pipe due to the reasons shown in (C) and (D), and the filling effect is insufficient.

(A) When a cable such as an optical fiber is present in the inner pipe, there is a problem that the organic material such as the cable covering material is softened due to the heat generation of hydration of cement or the like after the filling material is filled, causing performance deterioration. Had had.
(B) Due to the voids existing in the inner pipe, buoyancy is applied to the inner pipe when the filler is filled, which may cause damage to the inner pipe.
(C) When water has infiltrated into the outer pipe, there is a possibility that the filling of the filler may be hindered by the water.
(D) When filling the filling material inside without excavating the underground pipe structure, it is difficult to confirm the filling status, so that there is a possibility that voids may remain.

The present invention relates to a method of applying a filler between an inner pipe and an outer pipe of an underground pipe structure, which is composed of a double pipe of an inner pipe and an outer pipe and has a cable such as an optical fiber cable passed inside the inner pipe. When filling the filling material between the inner pipe and the outer pipe without greatly excavating the underground pipe structure, it does not cause damage or performance deterioration of the communication cable in the inner pipe, and the filling effect is due to poor filling. It is an object of the present invention to provide a method of constructing a filler without a possibility of insufficient filling material.

Therefore, as a result of various studies on the characteristics of the filler to be filled between the inner pipe and the outer pipe, the present inventor has found that the above problem can be solved by using a low heat generation type filler having a certain density, and the present invention has been made. Was completed.

That is, the present invention provides the following [1] to [6].

[1] A method of applying a filler between an inner pipe and an outer pipe of an underground pipe structure consisting of a double pipe consisting of a plurality of inner pipes and one outer pipe and having a cable passed inside the inner pipe. A method for constructing a filler, which comprises using a low heat generation type filler having a density of 1.15 to 1.35 kg / L.
[2] Only the end of the outer pipe of the double pipe is excavated, an injection pipe is inserted between the inner pipe and the outer pipe of the underground buried pipe structure from the excavated part, and the filler is passed through the injection pipe. The method for constructing a filler according to [1], which comprises injecting.
[3] Of the inner pipes, at least one filler hole and a water stop valve are provided in the inner pipe that does not pass through the cable in the underground pipe structure, and the filler is injected into the inner pipe that does not pass through the cable. The method for constructing a filler according to [1], wherein the filler is injected between the inner pipe and the outer pipe of the underground pipe structure through the ejection hole.
[4] The description according to [3], wherein a pipe camera provided with a guide tube is inserted into an inner tube through which the cable is not passed, and the filler is injected while observing the filling state of the filler with the pipe camera. Filling material construction method.
[5] The filling according to any one of [1] to [3], wherein the low heat generation type filler has a flow value (without falling motion) of 200 mm or more measured according to JIS R 5201 "Physical test method for cement". Material construction method.
[6] The density between the inner pipe and the outer pipe of the underground buried pipe structure, which consists of a double pipe consisting of a plurality of inner pipes and one outer pipe and through which a cable is passed inside the inner pipe, is 1.15 to 1.35 kg. An underground pipe structure characterized by being filled with a low heat generation type filler of / L.

The present invention relates to a method of applying a filler between an inner pipe and an outer pipe of an underground pipe structure, which is composed of a double pipe of an inner pipe and an outer pipe and has a cable such as an optical fiber cable inside the inner pipe. When filling the filling material between the inner pipe and the outer pipe without making a large excavation of the outer pipe of the double pipe, it does not cause damage or performance deterioration of the communication cable in the inner pipe, and the filling material due to poor filling. It is possible to provide a method of constructing a filler without a possibility that the filling effect of the filler is insufficient.

The schematic diagram of one aspect of the construction method of this invention is shown. The schematic diagram of one aspect of the construction method of this invention is shown. An example of how to insert a pipe camera is shown. The outline of the simple heat insulation test is shown. A schematic diagram of a formwork simulating an underground buried structure is shown.

The filler used in the construction method of the present invention is a low heat generation type filler having a density of 1.15 to 1.35 kg / L. Here, the density is the density (unit volume mass) after kneading the filler.
When filling the filler between the inner and outer pipes of the double pipe, the air existing between the inner and outer pipes of the double pipe or the air existing in the inner and inner pipes of the double pipe When filling the filler, buoyancy may be applied between the inner pipe and the outer pipe or the inner pipe. When the density of the filler exceeds 1.35 kg / L, the density difference between the inner pipe and the outer pipe or between the inner pipe becomes too large, and the buoyancy between the inner pipe and the outer pipe or the inner pipe becomes excessive. , May cause damage to the inner tube. When the density of the filler is less than 1.15 kg / L, it is obvious that the strength development is lowered, but there is a possibility that the material separation resistance is further lowered. The preferred density of the filler after kneading is 1.18 to 1.35 kg / L, and the more preferable density is 1.20 to 1.35 kg / L.

As a method for reducing the density, a method of mixing bubbles to form a foam mortar is well known, but in the case of bubbles, the bubble diameter may fluctuate greatly depending on the generator and environmental temperature, and due to the fluctuation of the bubble diameter. It is not preferable because the material separation resistance may vary. In order to introduce stable bubbles, for example, hollow microspheres, glass balloons, fly ash balloons, shirasu balloons, pearlite and the like can be used. Of these materials, it is particularly preferable to use factory-manufactured products in terms of quality stability.

Further, the filler used in the present invention is a low heat generation type filler.
Considering the softening point of the cable constituent material, the temperature inside the pipe after filling is preferably not more than 70 ° C, more preferably not more than 60 ° C, and even more preferably not more than 50 ° C. From this point of view, the filler needs to be a low heat generation type filler.
The low heat generation type filler in the present invention means a filler having a temperature rise of 30 ° C. or less in a simple heat insulation test. The amount of temperature increase is more preferably 20 ° C. or lower, and even more preferably 15 ° C. or lower. Here, the simple heat insulation test can be performed as follows.
Immediately fill the 0.7 liter plastic container installed in the thermos bottle (Dewar bottle) with the filler mixed with water, close the lid of the thermos bottle, and then reach the maximum temperature in the center of the filler. Measure the amount of temperature rise. The temperature is measured every 5 minutes with a thermocouple inserted in the center of the filler (see FIG. 4).

In order to obtain such a low heat generation type filler, the content of the hydraulic component in the filler is preferably 1 to 5 vol% at the time of kneading.
When filling the existing double pipe with mortar, it is preferable to carry out the work while maintaining a depth of 20 cm or more in the ground without excavating the entire double pipe. It is obvious that reducing the amount of hydraulic components such as cement reduces the calorific value, but if it is reduced too much, not only the strength at the time of curing will decrease too much, but also the material separation resistance may decrease. .. In the construction method of the present invention, since the filler can be filled while maintaining a depth of 20 cm or more in the ground where the temperature is stable, it is necessary if the amount of the hydraulic component at the time of kneading is in the range of 1 to 5 vol%. It is preferable because strength can be obtained. If the amount of the hydraulic component is too small, not only the strength development is lowered, but also the material separation resistance is greatly lowered, which is not preferable. Further, if the amount of the hydraulic component is too large, a part of the cable constituent material such as an optical fiber cable may exceed the softening point, which is not preferable. The content of the hydraulic component is more preferably 2 to 5 vol%, still more preferably 2.5 to 5 vol%.

As the hydraulic component in the filler used in the present invention, various Portland cements such as ordinary, early-strength, ultra-fast-strength, moderate heat, low heat, and sulfate-resistant, mixed cement, and arbitrary cement such as alumina cement can be used. can. In addition to the hydraulic component, stone powder such as silica stone, feldspar, pottery stone, and limestone, and inorganic powder such as kaolin, alumina, and bentonite can be used as the component that does not generate heat when in contact with water.

The filler used in the present invention is preferably excellent in fluidity from the viewpoint of filling into narrow voids, and the flow value (without falling motion) measured according to JIS R 5201 "Physical test method for cement" is 200 mm or more. Is preferable. If the flow value is less than 200 mm, the filling property is lowered and there is a possibility that voids may be formed in the pipe when filling the mortar, which is not preferable. The upper limit of the flow value is not particularly specified, but it is more preferably 300 mm or less from the viewpoint of material separation resistance. A more preferable flow value is 210 to 280 mm, and even more preferably 220 to 280 mm.

Further, when the material separation resistance is lowered, it is considered that the filling of the filler may be hindered by the water when the water has infiltrated into the outer pipe. In such a case, the water is not separated. It is preferable to include a sex-mixed material. It is more preferable to contain the inseparable admixture in water because it also has the effect of reducing the heat generation rate of the hydration-curing component such as cement. From the viewpoint of the effect of lowering the heat generation rate of hydration, the inseparable admixture in water is more preferably a cellulosic material, and most preferably hydroxypropylmethylcellulose.
When using an inseparable admixture in water, JSCE D-104 "Quality standard for inseparable admixture in water for concrete" is used as an index, and the pH value measured according to the standard is 12.0 or less. It is preferable from the viewpoint of material separation resistance. If the pH value exceeds 12.0, the material separation resistance may not be significantly improved, which is not preferable.

From the viewpoint of ensuring fluidity, the filler of the present invention preferably contains a dispersant such as a water reducing agent, an AE water reducing agent, a high-performance water reducing agent, a fluidizing agent, and a high-performance AE water reducing agent. From the viewpoint of material separation resistance, it is more preferable to use a dispersant other than the polycarboxylic acid type. Further, from the viewpoint of suppressing the temperature rise due to heat generation of hydration, it is more preferable to use a delayed dispersant.

In addition to this, components other than the above can be contained as long as the effects of the present invention are not impaired. Such components include, for example, thickeners, shrinkage reducing agents, defoaming agents, AE agents, swelling materials, fibers, pigments, coagulation retarders, coagulation accelerators, water retention agents, pozzolan-reactive substances, blast furnace slag fine powders. , Various aggregates and the like.

The type of water used for the filler of the present invention is not particularly limited. Any water such as tap water, river water, and groundwater can be used. The amount of water to be blended is not limited, but is preferably 30 to 100 parts by mass with respect to 100 parts by mass (solid component) of the filler from the viewpoint of ensuring fluidity that does not easily interfere with the construction.

The method of constructing the filler of the present invention comprises a double pipe of a plurality of inner pipes and one outer pipe, and is a filler between the inner pipe and the outer pipe of the underground buried pipe structure in which the cable is passed through the inner pipe. It is a construction method of the above, and is characterized by using the above-mentioned filler.
Here, the cable includes a communication cable such as an optical fiber cable and a metal cable, an electric power and a control cable, and the inner pipe is a communication pipeline through which the cable passes or a power pipe through which the electric power and the control cable pass. The road is mentioned. Further, the outer pipe includes a Hume pipe or the like that can withstand a load from the ground. The outer pipe is installed only under roads, railroad tracks, etc. where force is applied from above. The ends other than the inner pipe are closed with bricks or the like, and the space between the inner pipe and the outer pipe is usually hollow.

As one aspect of the construction method of the present invention, only the end portion of the outer pipe of the double pipe is excavated, and the injection pipe is inserted between the inner pipe and the outer pipe of the underground buried pipe structure from the excavated portion. A method of injecting a filler through an injection tube can be mentioned (see FIG. 1).

In the construction method of this aspect, for example, as shown in FIG. 1, an injection pipe may be inserted between the inner pipe and the outer pipe from the above-ground portion, and the filler may be injected through the injection pipe. Since the underground pipe structure is a closed space, it may not be possible to inject smoothly without air bleeding, so it is preferable to provide at least one air bleeding pipe, and it is more preferable to provide two or more air bleeding pipes. ..
In the aspect of FIG. 1, after excavating the ground, a hole is made in a part of the closed end portion of the outer pipe, and an injection hose is inserted.

As another aspect of the construction method of the present invention, at least one filler ejection hole (injection hole) and a water stop valve are provided in the inner pipe of the inner pipe not passing through the cable in the underground pipe, and the cable is provided. A method of injecting a filler into an inner pipe that has not passed through the pipe and injecting the filler between the inner pipe and the outer pipe of the underground buried pipe structure through the ejection hole can be mentioned.
More specifically, a pipe camera (line scope) provided with a guide tube is inserted into the inner pipe not passing through the cable, and the filler is injected while observing the filling state of the filler with the pipe camera (see FIG. 2). ). That is, when filling the existing double pipe with the filler, the injection pipe is inserted from the manhole into the inner pipe of the underground pipe structure without excavating the double pipe and keeping the depth of 20 cm or more in the ground. Insert and inject the filler through the injection tube. The filler injected into the inner pipe is ejected from one or more spouts provided in the inner pipe, and is filled between the inner pipe and the outer pipe. Further, it is preferable to lay a guide pipe separately from the injection pipe, insert a pipe camera inside the guide pipe, and fill the filling material while observing the filling state with the pipe camera. In addition, this guide tube can also serve as an air bleeder (Fig. 2). At the final stage of filling work, the pipe camera is removed. The filler eventually penetrates the guide tube from which the pipe camera has been extracted, passes through the guide tube, and returns into the manhole. From this, it can be determined that the filler is sufficiently filled in the cavities of the inner pipe and the outer pipe. FIG. 3 shows an enlarged view of the state of the guide tube and the pipe camera.

Normally, the inner pipe of a communication pipe or the like has a gentle ascending slope from the manhole to the double pipe portion, and the outer pipe (Hume pipe) itself is often sloped as well. When the outer pipe is inclined, it is preferable to fill it from below, so that the ejection hole is preferably installed near the end of the outer pipe. As a result, the filler can be filled without gaps. On the other hand, it is preferable that the pipe camera is installed near the end of the outer tube on the opposite side of the ejection hole. This makes it possible to grasp the filling status until the end.

As a specific construction procedure, first, a special drilling device is introduced from the manhole into the inner pipe, and a ejection hole for the filler and an insertion hole for inserting the pipe camera are drilled at a predetermined place. The hole is provided on the upper side of the inner tube. Next, a water stopcock is installed at the end of the drilled part. Next, a guide tube (outside) for inserting the pipe camera is inserted. As this guide tube (outside), a vinyl chloride tube or the like having an outer diameter of about 20 mm can be used. After the guide tube (outside) is installed in the pipe camera insertion slot, the guide tube (inside) for passing the pipe camera is inserted. The guide tube (inside) passes through the inside of the guide tube (outside) and is inserted into the hollow portion of the inner tube and the outer tube. It is inserted up to the top of the outer tube. A flexible hose is used as the guide tube (inside). Then, the pipe camera is inserted into the guide tube (inside), and the cavities of the inner tube and the outer tube are installed at observable positions.

When injecting the filler, the filler injection pipe (injection hose) is inserted into the inner pipe. A kneading device (mixer) and a pump for pumping are usually installed in the above-ground part of the filler, and the filler is injected into the inner pipe through the injection pipe. A water stopcock is also installed at the inlet of the inner pipe so that the filler does not leak from the inlet of the inner pipe.

As described above, it is preferable not to excavate the outer tube of the double tube for stabilizing the temperature inside the tube. Stabilization of the temperature inside the pipe is preferable because it leads not only to stabilization of strength development but also to stabilization of the maximum temperature at the time of heat generation and stabilization of material separation resistance. Since it is known that the underground temperature is almost stabilized at a depth of 20 cm, it is not necessary to bury it deep in the ground. In particular, if the entire pipe is excavated in midsummer, the temperature inside the pipe may become higher than the air temperature due to solar radiation, and the maximum temperature rises due to the heat generated by hydration of the filler, which greatly increases the risk of cable softening. Not preferred.

Further, since the outer pipe of the double pipe is not excavated, it is difficult to observe the filling state at the time of filling the filler, and filling defects are likely to occur, which is not preferable. In the present invention, by filling while observing the filling state with a pipe camera, it is possible to prevent the occurrence of filling defects.

Hereinafter, examples of the present invention will be shown together with comparative examples.
(1) Adjustment of filler Ordinary Portland cement (manufactured by Taiheiyo Cement Co., Ltd.) as a hydraulic component, silica stone powder (manufactured by Chichibu Kogyo Co., Ltd.) as a component that does not generate heat, and pearlite ("Pacific pearlite" manufactured by Taiheiyo Cement Co., Ltd.) as a density adjusting material. used. The composition of the filler composition was adjusted so that the filler after kneading had a predetermined density (unit volume mass) and the amount of heat-generating components. The density of the filler was 1.30 kg / L, and the amount of the hydraulic component in the filler was 4.3 vol%.
On the other hand, as a comparative example, a commercially available low heat generation type filler and a lightweight filler were used.

(2) Kneading of filler The above-mentioned filler composition and commercially available product are kneaded for 120 seconds with a hand mixer (manufactured by Hitachi, Ltd., rotation speed 1100 rpm) by adding water (tap water) in a constant temperature test chamber at 20 ° C. , A test sample was prepared.
The flow value of each filler after kneading was adjusted to 250 ± 20 mm.

(3) Evaluation test 1) Unit volume mass Using a steel columnar container with an internal volume of 0.5 liter, measurement was performed according to the method of JIS A 1171 "Test method for polymer cement mortar".
2) Curing status after 7 days at 20 ° C Molding is performed using a resin formwork of φ50 mm × H100 mm according to the method of JIS A 1108 “Compressive strength test method of concrete”, and a constant temperature test chamber at 20 ° C. After 7 days, the mold was removed from the mold, and those that could be removed (the ones that did not lose their shape) were evaluated as ◯, and the others were evaluated as x.
3) Amount of temperature rise under simple heat insulation conditions After the filling material that has been kneaded is immediately filled in a plastic container with an internal volume of 0.7 liters installed in a thermos bottle (Dewar bottle) and the lid of the thermos bottle is closed. , The amount of temperature rise when the maximum temperature of the center of the filler was reached was measured. The temperature was measured every 5 minutes using a data logger (manufactured by Tokyo Sokki Co., Ltd.) with a thermocouple inserted into the center of the filler (Fig. 4).
4) Bleeding rate Measurement was performed according to the method of JIS A 1123 "Concrete bleeding test method".
5) Flow test Measured according to the method of JIS R 5201 "Physical test method of cement".

(4) Test results Table 1 shows the test results. It can be seen that in the product of the present invention, the simple adiabatic temperature rise is reduced while the predetermined fluidity and unit volume mass are secured. In addition, there was no bleeding, and the curing condition after 7 days was good.

(5) Filling test using a simulated underground structure Filling into a formwork (inner diameter 1 m x height 1.2 m) simulating an underground structure in a constant temperature room at 20 ° C using the formulation of the above example. A test was conducted. The formwork is shown in FIG.
Kneading of the filler was carried out using a grout mixer. The filler after kneading was pumped by pressure using a squeeze pump to fill the mold. The temperature inside the filler in the pipe after filling was measured with a thermocouple.
It was confirmed that filling into the pipe can be carried out without any problem by using the filler of the present invention. Further, it was confirmed that the temperature inside the filler was 43 ° C. at the maximum, and the amount of temperature rise was suppressed within 25 ° C.

Claims (3)

It is a method of installing a filler between the inner pipe and the outer pipe of the underground buried pipe structure, which consists of a double pipe of a plurality of inner pipes and one outer pipe, and a cable is passed through the inner pipe. However, it is a low heat generation type filler having a density of 1.15 to 1.35 kg / L.
Of the plurality of inner pipes, at least one filler hole and a water stop valve are provided in the inner pipe that does not pass through the cable in the underground pipe structure, and the filler is injected into the inner pipe that does not pass through the cable. A method for constructing a filler, which comprises injecting a filler between an inner pipe and an outer pipe of an underground pipe structure through a ejection hole . The filler according to claim 1 , wherein a pipe camera provided with a guide tube is inserted into an inner pipe not passing through the cable, and the filler is injected while observing the filling state of the filler with the pipe camera. Construction method. The method for constructing a filler according to claim 1 or 2 , wherein the low heat-generating filler has a flow value (without falling motion) of 200 mm or more measured according to JIS R 5201 "Physical test method for cement".

Images